Humanlike mechanical finger for prostethic hands and massaging device with humanlike mechanical fingers

ABSTRACT

Presented invention provides mechanical finger which visually and functionally resembles the human one and will be primarily used in the prosthetic hands. The finger consists of three phalanges pivoted in their clevises. The first phalange is driven by the rod located in the arm and being connected to the actuator. The second and third phalanges are driven by the tendons. The tension of the second phalange tendon is initiated by the movement of the first phalange and the tension of the third phalange tendon is initiated by the movement of the second phalange. Degree of the movement of the first phalange is determined by the actuator and degree of the movement of the second phalange is determined by the amount of slack given to the first tendon by another rod located in the arm and being adjustable lengthwise or being connected to the second actuator. Degree of the movement of the third phalange, like in human finger is strictly related to the degree of movement of the second phalange and is determined by the length of the second tendon. Back to the straight position first phalange returns by the driving rod movement in opposite direction or by the spring if driving rod is activated only in one direction and released. The second and third phalanges return back to the straight position by their own common spring. All phalanges with attached elements as well as a palm structure are covered by a flesh imitating material and will resemble the human hand as close as human flesh imitators can be provided by today&#39;s technology. The massaging device presented in this invention uses described above bendable finger and unbendable thumb. Opening and closing fingers create pinching action. The device is intended to be primarily used in the chairs of the pilots and drivers to provide relaxation massage to the shoulders and lower back areas during long journeys but it can be easily adapted to the three or four fingers/claws gripping device and can be used in the rescue and exploration operations as well as in the machinery.

BACKGROUND OF THE INVENTION

Author of the invention while at occupational therapy has noticed that human fingers are the most efficient tools in performing massaging therapy on damaged tissues around the scars. Among many available massaging devices one with the humanlike fingers is missing. Work on the project produced massaging device prototype with two unbendable fingers. Their massaging action was not as good though as an action of the straight thumb and bendable index finger or middle finger. Successful design of bendable finger has revealed a great opportunity for using it in the future development of the prosthetic hands. Upon review of the previous US patents in the field of mechanical fingers, hands and grasping devices and comparing their fingers and palm designs to the one presented here it becomes apparent that presented here solutions can make a real progress in creating practical and affordable prosthetic hand. Most of the previous designs are complicated, expensive and they give very little if any consideration to the esthetic side of the prosthesis. Those designs are more suitable for the robotic rather than for the human applications. Prosthetic hand constructed with presented here fingers will not only look like the real one but will be able to perform a few simple tasks in it basic form as well as multiple tasks in it most developed and computerized form.

REFERENCES CITED

U.S. Patent Documents 3,694,021 September 1972 Mullen 3,866,966 February 1975 Skinner, II 3,927,424 December 1975 Itoh 4,377,305 March 1983 Horvath 4,834,443 May 1989 Crowder et al. 4,980,626 December 1990 Hess et al. 4,984,951 January 1991 Jameson 4,986,723 January 1991 Maeda 5,080,681 January 1992 Erb 5,108,140 April 1992 Bartholet 5,200,679 April 1993 Graham 5,280,981 January 1994 Schulz 5,378,033 January 1995 Guo et al. 5,762,390 June 1998 Gosselin et al.

SUMMARY OF THE INVENTION

Presented here finger is operated by the rods, tendons and springs. Compacted design of the finger allows having it in the natural size and be covered by a flesh imitator. Applications are versatile and allow creating variations of the prosthetic hands in order to satisfy individual needs of amputees. The most basic and most affordable design of the prosthetic hand would be the one with the second phalanges adjustable rods being anchored in the arm and inactive after choosing desirable tension to the first tendon and giving the biggest slack to the thumb or adjustable rods being abandon altogether and the first tendons anchored to the back of the palm below the first phalange after deciding on the proper length of the tendons. All of the first phalanges activating rods would be connected to the one common element which would be activated one way only by the pneumatic pressure preferably and being pushed back by the spring upon the release. This hand would perform a basic grasping grip and assist amputees in the simple tasks like holding a steering wheel, a joystick, a hand bag, a glass, a railing and as such. The hand opening and closing button would be operated by the toe as an example. The last and the most developed form of the prosthetic hand would be the one with most of the rods connected to the separate actuators operated by servomotors or solenoids. The computer chip would allow activating a combination of different rods and performing different grips on the voice command . . . . For example command “SPOON” would first activate driving rods of pinky, ring, and the middle finger to close them partially and activate afterwards driving rod of the index finger and the thumb as well as the thumb adjusting rod to give more slack to its first tendon. The commands “PEN” or “PINCH” would perform the same or very similar grip. On the command “PIANO” all fingers would bend except for the index finger which would be kept straight to perform typing like tasks. In the middle between basic and the most developed forms of prosthetic hands there would be some special order designs with only few actuators to perform selected tasks or some custom made like for example one with the first phalanges pivoting ears being positioned on the palm with slightly bigger angles between them so the fingers in the open position will be spread more apart to perform task of grasping larger, grapefruit like objects. All variations of prosthetic hands will use the same unchangeable elements. Similar elements can be also used for the wrist design. Just two more ears added at the base of the arm, two more clevises in the palm, connecting pins and the driving rod. Presented here massaging device can be easily mounted not only in the back of the chair as shown on the drawing but also can be accommodated into other structures like benches, mats and as a such with the purpose to use it in the spas, gyms, physiotherapy clinics as a multiple massaging units. It can be also used as a single unit being hold in one hand and providing massage to the different parts of the body and most likely being used as a masseur's helper. The other possible applications will be explained in the description of the drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1

It is the front view of the finger without a flesh imitator. It shows first phalange 1, second phalange 2, third phalange 3, first tendon 4, second tendon 5, activating rod 6 and rod's guiding pin 9. Each phalange has a clevis at the bottom and one ear at the top. Guiding pin 9 is placed with loose in the round holes made across the ears placed on the palm structure and has a role to allow side movements of the upper part of the rod while restricting undesirable side movements of the lower part of the rod. The driving rod protrudes with the loose through the hole made across said pin 9. This will allow for the unrestricted up and down movement of the driving rod. On the palm structure are shown two more single ears for mounting the neighboring fingers.

FIG. 2

It is the main section of the finger and describes all the mechanics of the presented invention. ‘It shows driving rod 6 placed in the clevis of the first phalange 1 and connected to that phalange by the pin 12 which is press fitted in the clevis and loose in the rod. In the middle of the first phalange 1 there is an opening through which protrudes first tendon 4. Said tendon 4 can be anchored to the back of the palm structure or, as shown here, can be connected to the adjustable rod 7. The other end of the tendon 4 is firmly connected to the front bottom of the second phalange 2 by an any means of the firm connection, and depending on the materials used, it can be glued, thermo integrated with the second phalange's material, connected by a mechanical fasteners and as such. The same connection applies to the both ends of the second tendon 5 which is permanently anchored to the back of the first phalange, protrudes through the middle opening of the second phalange and is firmly connected to the front of the third phalange 3. The similar fastening will also apply to the bottom end of the flat spring 8 which is permanently connected to the top back of the first phalange. The top end of said spring 8 protrudes through the slot placed at the back of the third phalange. The role of the spring is to straighten second and third phalanges upon up movement of the rod 6. The spring can be single flat or multiple flats depending on the version of the prosthetic hand and the flexibility of the flesh imitating material. Pins 10 connect first phalange to the palm structure and the second phalange to the first phalange. The smaller pin 11 connects phalange 3 with phalange 2. The pins are press fitted in the clevises and having a loose in the ears. Upon the movement of the first phalange initiated by the down moving rod 6 the first tendon 4 will be stretched because it's bottom end is not attached to the pivot point of the phalange 1. This tension of the tendon will initiate movement of the second phalange. Similarly the movement of the third phalange will be initiated by the stretch of the second tendon upon movement of the second phalange. The length of the tendons as well as a shape of the bottom back of first and second phalanges will determine amount of the stretch of the tendons and therefore will determine degree of the movement of the phalanges. The tension of the first tendon can be also adjusted by the down or up movement of the rod 7 and will apply mostly to the thumb finger because thumb for most of the grips, has a different timing for closing than remaining four fingers. It is believed that for all fingers the third phalanges degree of movement don't need any adjustments as they are moving in the strict relation with the second phalanges except for the thumb again. But in order to accommodate for the fundamental movements steering elements for all the fingers in the arm limited space, some secondary functions are intended to be abolished as the goal of this invention is not to create perfect human prosthetic hand but rather more simple, yet practical, reliable and affordable one.

FIG. 3

It is the side view of the bottom part of the phalange 2 and the phalange 3. It shows clevises and ears configuration at the pivot point. They are shaped to make a contact in the point P and keep phalanges in the straight position when open and prevent them from over bending by the action of the spring 8.

FIG. 4

It is the back view on adjustable rod 7 and second phalange tendon 4. It shows the one of many possible connections between them throughout pin 11 which is press fitted in the rod's clevis.

FIG. 5

It is the section throughout guiding pin 9 and protruding across it activating rod 6 shown and described previously on FIG. 1. The same mechanism is used also in the massaging device FIG. 7 for connecting fingers 4 and 5 with disc 3.

FIG. 6

It is the cross section of the top of the third phalange 3. It shows slot at the back of phalange throughout which protrudes spring 8.

FIG. 7

It is the main section of the massaging device installed in the back of the chair. It shows all the parts used and describes mechanics of said massaging device. Cylinder 1 is threaded on its outside bottom diameter and is fastened to chair's structure by nuts 7. Special washers 8 are having unparallel surfaces on both sides what allows to adjust device's mounting angle on the chair. Inside cylinder 1 is placed piston 2 sealed with O rings 14. The bottom boss of the piston 2 is out of round to accommodate for the gripping tool during assembly. Under the bottom of the piston is placed spring 6 and washers 10 and 11. Bottom inside diameter of the cylinder 1 has thread to connect closing plug 9. Connection is sealed by gasket 17. In upper part of the cylinder there is threaded side hole in which is placed nozzle 12. Hose 16 is attached to the nozzle and secured by clip 18. Upper part of the cylinder 1 has a bigger diameter to accommodate for the fingers 4 and 5 as well as the driving disc 3. Said driving disc 3 is round and is guided with loose in the hole made in the top of cylinder 1. Disc 3 has two slots opposite to each other and two round holes across the slots. In said across holes are placed with loose guiding pins 13 which have round holes across them as well. Disc 3 has a threaded hole in the centre and is connected through it with the rod of the piston 2. Cylinder 1 has a hole in the centre between the lower and the upper part of the body. Through this hole protrudes piston's 2 rod and it is sealed with the O ring 15. The upper body of the cylinder 1 has a ring shape created by outside diameter and inside hole for disc 3. In this ring are made two slots opposite to each other with the round holes across them. In those slots are placed fingers 4 and 5 which are connected to the body of said cylinder 1 with the pins 18 press fitted in the across holes. This connection is the same one than between the finger and the palm structure and was earlier described on FIG. 1 and FIG. 2. Also the finger 4 is the same than earlier described on FIG. 1, FIG. 2, FIG. 3 and FIG. 6. The only difference is that the bottom back clevis of the first phalange is reshaped into the single ear and the front bottom clevis to connect activating rod is eliminated and this part of the phalange is shaped into the round pin. Those round pins of the bottom of the fingers 4 and 5 are protruding with loose through across holes of the guiding pins 13. Said guiding pins 13 are acting the same way than earlier described on FIG. 1 and FIG. 5 guiding pin 9. They will turn in their round holes of the disc 3 during up and down movement of said disc what will allow for sliding in them round bottom pins of the fingers 4 and 5 and therefore allow unrestricted movement of the fingers. In the described above design there are two fingers which are intended to imitate pinching action of the thumb and the index or the thumb and the middle finger. One or two more slots can be added though to the upper ring of the cylinder 1 as well as to the driving disc 3 and one or two more fingers can be accommodated into these slots. It is believed that multiple fingers would be made rather as a claws shaped specifically to match the shape of the object to be moved. The presented here massaging device is powered preferably by pressurized air what will allow to install multiple units in the chair or other structure and operate them by the one single pump. The air supplied through hose 16 will drive piston 2 down and together with it will drive down disc 3. Down movement of the disc 3 will create closing action of the finger 4 and finger 5 together with the bending action of the finger 4 as per previous description. The opening of the fingers is done by the action of compressed spring 6 upon release of the air pressure. 

1-18. (canceled)
 19. Presented here mechanical finger covered by the flesh imitating material resembles human one in appearance, size and functionality and allows to build variations of prosthetic hands which can be functional by using one actuator only, perform different tasks and resemble human hand in appearance and functionality.
 20. Presented here mechanical finger is operated by rods, tendons and springs where the second phalange tendon is connected to the front of said second phalange, protrudes through the first phalange and is anchored at the back of said first phalange and the third phalange tendon is connected to the front of said third phalange, protrudes through the second phalange and is anchored at the back of said second phalange.
 21. The movement of the second phalange is initiated by the movement of the first phalange and the movement of the third phalange is initiated by the movement of the second phalange where a degree of movement of the second phalange is regulated by the amount of the slack given to the second phalange tendon and a degree of movement of the third phalange is strictly related to the degree of movement of the second phalange and will depend on the second tendon tension.
 22. Mechanical fingers mounted in prosthetic hand are returning to the straight position by the action of driving rod or the spring straightening the first phalange and one common spring straightening the second and the third phalanges.
 23. Presented here massaging device provides massage by the pinching action of one bendable and one straight finger where fingers opening and closing motion is transferred to said fingers from the straight line moving element connected to the cylindrical ends of the fingers by the pins with the cross holes.
 24. The mechanism of two fingers massaging device can be accommodated into single massaging device or multiple massaging devices installed in the chairs, benches, and jacuzzis as well as into multiple fingers or multiple claws device installed in other structures and used for industrial and medical purposes or in the rescue and exploration operations. 